The invention is with respect to an apparatus for sucking up and holding sludge, more specially in the form of a sewer cleaning and/or clearing vehicle, having a suction line opening into a sludge tank on a carriage, the tank having a sludge outlet with a sludge outlet door for shutting it, and a water outlet, able to be used separately therefrom, the water outlet having an overflow line having, at an inlet end thereof, a filter unit in the sludge tank, and at least one jet cleaning unit for jetting water onto said filter unit.
An apparatus on these general lines is to be seen in German Auslegeschrift specification No. 2,736,587 in the form of a sewer cleaning vehicle in which water is processed. In the case of this known system, the overflow line is designed opening into a water tank from which water is taken by a high pressure pump and pumped into a clearing hose which may be lowered into a sewer to be cleaned. The overflow line is, in this case, put into operation by putting the sludge tank under pressure. The filter unit is cleaned by water coming from the high pressure pump. A shortcoming in this respect is that, for forcing the water from the sludge tank into the water tank, suction operation, taking place on evacuating the sludge tank, has to be stopped for the time being. Furthermore, the flushing operation using the clearing hose has to be stopped. Because some of the water coming from the high pressure pump is used for filter cleaning, there will be a drop in the pressure in the clearing hose to such a level that the jet of water coming from the clearing hose and used for cleaning purposes, is shut down. For this reason, no non-stop operation of this known system is possible.